Porous film cartridge

ABSTRACT

A porous membrane cartridge of the present invention is configured to comprises a cylindrical barrel having openings at a top end and a rear end, respectively; a cap formed into a cylindrical shape having a fit-in portion fitted outside the top end, abutting with an opening edge of the top end, and having a sandwiching face for sandwiching a porous membrane between itself and the barrel; and the porous membrane sandwiched between the opening edge of the barrel and the cap, wherein the cap is fixed to the barrel so as not to be pulled out of the barrel in a state of crushing a peripheral edge of the porous membrane and sandwiching the porous membrane between itself and the cap.

TECHNICAL FIELD

The present invention relates to a porous membrane cartridge used for afiltration of a liquid and the like.

BACKGROUND ART

A porous membrane is widely used in a laboratory and a factory for afiltration of a liquid and an adsorption of a specific substance in theliquid. Then in using the porous membrane for such a purpose, it isrequested to hold the porous membrane on the way of a passage where theliquid passes. As the holding method is generally used a method ofholding the porous membrane with sandwiching it between two membershaving a passage where the liquid passes.

Because such a porous membrane is generally used in a precise experimentand measurement, a purified one is requested and is usually changed ifonce used. Therefore, it is convenient in points of a purification andan expedience in use to make a porous membrane a cartridge holding theporous membrane in a state of being able to pass a liquid therethrough.As such a porous membrane is known, for example, such a nucleic acidrefining unit described in Japanese Patent Laid-Open Publication No.2002-345465.

DISCLOSURE OF THE INVENTION

However, in a conventional porous membrane there is a fear that a liquidto pass the porous membrane goes around a side thereof. Particularly, ina case that two components for sandwiching the porous membrane are fixedonly by fastening with fit-in, a size changes according to an expansionby a temperature change and swelling by a humidity change, and asandwiched state changes in some case. In addition, in a case of usingthe conventional porous membrane in refining a nucleic acid, althoughthe nucleic acid is adsorbed to the porous membrane, then is adsorbed tothe porous membrane, and making a specific liquid flow, the nucleic acidis desorbed; however, if unable to make the liquid for desorptionsufficiently flow also in corner portions of the porous membrane, thereis a problem that: the nucleic acid remains in the corners and arecovery efficiency of the nucleic acid worsens. In view of such aproblem, the present invention is made, and a purpose thereof is toprovide a porous membrane cartridge for preventing a liquid from goingaround a side portion thereof.

In order to solve the problem, a porous membrane cartridge of thepresent invention is configured as follows: Namely, the porous membranecartridge comprises a cylindrical barrel having openings at a top endand a rear end, respectively; a cap formed into a cylindrical shapehaving a fit-in portion fitted outside the top end, abutting with anopening edge of the top end, and having a sandwiching face forsandwiching a porous membrane between itself and the barrel; and theporous membrane sandwiched between the opening edge of the barrel andthe cap, wherein the cap is fixed to the barrel so as not to be pulledout of the barrel in a state of crushing a peripheral edge of the porousmembrane and sandwiching the porous membrane between itself and the cap.

In accordance with such a porous membrane cartridge, an opening edge ofa barrel and a sandwiching face of a cap are sandwiched in a state of aperipheral edge of the porous membrane being crushed. In other words, ifbecause the porous membrane has a porosity, it is strongly sandwiched bythe sandwiching face between the opening edge of the barrel and thesandwiching face of the cap, the porosity is crushed as if occluded, anda liquid results in not flowing therefrom. Then because in the porousmembrane cartridge the cap is fixed to the barrel in this state, theliquid does not go around a side portion of the porous membrane.Accordingly, when using the porous membrane cartridge in filtration andadsorption, it is enabled to prevent a discharged liquid from beingcontaminated by a liquid going around the side portion of the porousmembrane.

As a method of fixing the cap to the barrel can be used any one of afit-in, adhesion, ultrasonic welding, laser welding, insert molding, andthe like. To be more precise, it is preferable that the opening edge ofthe barrel and the sandwiching face of the cap are welded by ultrasound.

Then, in addition that the opening edge of the barrel is formed to ataper where an inner perimeter side is more retreated than an outerperimeter side, it is preferable that the opening edge of the barrel iswelded to the sandwiching face of the cap by ultrasound. Thus because inaddition to crushing a peripheral edge of the porous membrane by aportion of an outer perimeter side, welding can be performed by theportion of the outer perimeter and a sandwiching force of the porousmembrane gradually becomes smaller as the porous membrane draws apartfrom the welded portion (namely, the portion of the outer perimeter), itis enabled to avoid a stress on the porous membrane from concentratingand to prevent a breakage thereof from occurring. At this time, becauseif the taper is continuously formed into a flat portion formed at anoutmost perimeter of the opening edge, it sandwiches the porous membraneby a clear welded portion (energy director), it is enabled to reduce anunnecessary positional displacement of the porous membrane.

In this case, in addition to sandwiching and crushing the porousmembrane between the outer perimeter side of the opening edge and thesandwiching face, it is preferable that a portion of the outer perimeterside and that of the sandwiching face are welded therebetween byultrasound as it is.

In addition, a porous membrane cartridge may also be configured by:circularly forming a bead portion as a welded portion (energy director),additionally the porous membrane is sandwiched and crushed with the beadportion, and the cap and the barrel are welded by ultrasound.

In addition, any one of the adhesion portion and welded portion of thebarrel and the cap is not limited to the opening edge and thesandwiching face. For example, the barrel may also have a joint portionfor abutting with an opening edge of a fit-in portion of the cap on ownouter perimeter face, make the cap and the barrel adhere or be weldedbetween the opening edge and the joint portion, and thereby configure aporous membrane cartridge. Thus, if sandwiching a porous membrane andjointing a barrel and a cap at separate portions, it does not occur todamage the porous membrane even in a case of using an especiallydelicate porous membrane.

Furthermore, in a case of fixing the cap by fitting in the barrel, it isenabled to fix the cap to the barrel by an engagement between any one ofa depression and a protrusion formed on an outer perimeter face of thebarrel and any one of those formed on an inner perimeter face of thecap. At this time, not to mention an engagement between the depressionon the outer perimeter face of the barrel and the protrusion on theinner perimeter face of the cap and an engagement between the protrusionon the outer perimeter face of the barrel and the depression on theinner perimeter face of the cap, the protrusion on the outer perimeterface of the barrel and the protrusion on the inner perimeter face of thecap may be engaged.

In addition, not limiting to the portions described above, it is alsoenabled to fix the cap and the barrel by any one of an adhesive andlaser welding on a fit-in face where the outer perimeter face of thebarrel and the inner perimeter face of the cap oppose each other.

In addition, in a case of performing molding by insert molding, it ispreferable to place a cap molded in advance and a porous membranedisposed in the cap within a cavity of an injection molding mold, toinject a molding material in the cavity, to thereby mold the barrel, andto simultaneously sandwich a porous membrane with the opening edge ofthe barrel and the sandwiching face of the cap. Thus it is enabled torealize a sandwich and fixation of the porous membrane. In addition, ina case of making a porous membrane cartridge unit where a plurality ofporous membrane cartridges are connected, it is enabled to align asandwiching force of porous membranes of the plurality of the porousmembrane cartridges, and while simultaneously forming a plurality ofbarrels, to make up a state of these barrels being stably connected.

In accordance with a porous membrane cartridge of the present inventionthus described, it is enabled to prevent a liquid from going around aside portion of the porous membrane.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded perspective view of a porous membrane cartridgerelated to a first embodiment of the present invention.

FIG. 2 is a section view of a porous membrane cartridge related to thefirst embodiment.

FIG. 3 is an enlarged section perspective view of a cap related to thefirst embodiment.

FIG. 4 is an enlarged view of a part A in FIG. 2, and shows a statebefore a barrel 10 and a cap 20 are welded.

FIG. 5 is drawings showing a process of assembling a porous membranecartridge related to the first embodiment; (a) shows a state beforewelding; (b) shows a state of starting to crush a porous membrane F; (c)shows a state on the way of the welding; and (d) shows a state after thewelding.

FIG. 6 is section views showing a porous membrane cartridge 1A relatedto a second embodiment of the present invention and corresponding to theenlarged view of the part A in FIG. 2; (a) shows a state before welding;(b) shows a state on the way of the welding; and (c) shows a state afterthe welding.

FIG. 7 is a section view showing another example of the porous membranecartridge 1A related to the second embodiment and corresponding to theenlarged view of the part A in FIG. 2.

FIG. 8 is drawings showing a porous membrane cartridge 1D related to athird embodiment of the present invention and corresponding to theenlarged view of the part A in FIG. 2; (a) shows a state before welding;and (b) shows a state after the welding.

FIG. 9 (a) is another example of the porous membrane cartridge 1D of thethird embodiment; and FIG. 9 (b) shows still another example.

BEST MODE(S) FOR CARRYING OUT THE INVENTION First Embodiment

Next will be described an embodiment of the present invention, referringto drawings as needed. FIG. 1 is an exploded perspective view of aporous membrane cartridge related to a first embodiment of the presentinvention; FIG. 2 is a section view of a porous membrane cartridgerelated to the first embodiment; and FIG. 3 is an enlarged sectionperspective view of a cap related to the first embodiment.

Meanwhile, although in the embodiment is described a case of using aporous membrane cartridge in a nucleic acid as an application thereof,the application is not limited thereto.

As shown in FIG. 1, a porous membrane cartridge 1 related to the firstembodiment is configured of a porous membrane F, and a barrel 10 and acap 20 for holding the porous membrane F and forming a passage where aliquid passes.

The barrel 10 comprises a cylindrical main body portion 12 and acylindrical top end 13 continuing into the main body portion 12, and hasan opening 11 a at the top end 13 and an opening 11 b at a rear end ofthe main body portion 12. Therefore, a liquid is enabled to pass fromthe opening 11 b to the opening 11 a. An outer diameter of the top end13 is designed to be one size smaller that of the main body portion 12.Meanwhile, in the embodiment a side of the barrel 10 and the cap 20 inwhich a liquid flows is called a rear end, and a side from which theliquid is pushed out is called a top end.

The cap 20 comprises a cylindrical fit-in portion 22 and a nozzle 23continuing into a top side of the fit-in portion 22.

An opening 21 a is formed at the top end of the nozzle 23, an opening 21b is formed at the rear end of the fit-in portion 22, and thus a liquidis enabled to pass from the rear end to top end of the cap 20.

An inner diameter of the fit-in portion 22 is formed into a diameterenabled to fit in the diameter of the top end 13 of the barrel 10.

Then as shown in FIG. 2, by fitting the top end 13 of the barrel 10 inthe fit-in portion 22 of the cap 20 in a state of putting in the porousmembrane F into the portion 22 of the cap 20, it is enabled to sandwichthe porous membrane F between the cap 20 and the barrel 10.

As shown in FIG. 3, in the cap 20 are formed six radial ribs 25 (onlythree are shown in FIG. 3) at a bottom portion 26 of the fit-in portion22 continuing into the nozzle 23 from the portion 22. In addition, at anouter perimeter edge of the bottom portion 26, across a whole perimeterthereof is formed a sandwiching face 24 made higher by one step from thebottom portion 26 so as to be a same height as an upper face of the ribs25.

The sandwiching face 24 is a face for sandwiching the porous membrane Fbetween itself and an opening edge 14 (see FIG. 1) corresponding to anend edge of the opening 11 a of the barrel 10.

The ribs 25 are formed at the same height as the sandwiching face 24,thereby support the porous membrane F disposed at the bottom portion 26within the cap 20, and prevent the porous membrane F from elongating andbreaking by a liquid flowing into the top end (opening 21 a) from therear end (opening 21 b). In addition, the ribs 25 are radially formed,and thereby, it is designed that a liquid smoothly flows in the nozzle23 in being made to flow from the rear end to the top end.

Meanwhile, although the barrel 10 and the cap 20 are composed ofpolystyrene, they are not limited thereto. In a case of fixing thebarrel 10 and the cap 20 by ultrasonic welding, a thermoplastic resin isavailable that can be welded by ultrasound. In addition, in a case offixing the barrel 10 and the cap 20 by adhesive, a material is availablethat can be made to adhere by adhesive.

The porous membrane F is composed of an organic polymer and is formedinto a circle of which a diameter approximately matches the innerdiameter of the cap 20 and the outer diameter of the top end 13 of thebarrel 10. As a material of the porous membrane F, for example, asurface-saponified substance of acetylcellulose is suitable. Asacetylcellulose, although any one of mono acetylcellulose,diacetylcellulose, and triacetylcellulose is available, specificallytriacetylcellulose is preferable.

Meanwhile, as a general filter can also be used a porous membrane ofsuch PTFE (polytetrafluoroethylene), polyamide, polypropylene, andpolycarbonate.

FIG. 4 is an enlarged view of a part A in FIG. 2.

As shown in FIG. 4, in the opening edge 14 of the barrel 10, a slightportion (for example, a degree of 0.1 mm width) from an outmostperimeter is formed as a flat portion 14 a perpendicular to an axialline (longitudinal direction) of the barrel 10, and continuing into theflat portion 14 a is formed a taper portion 14 b that becomes an insidetaper that gradually retreats from an outer perimeter toward an innerperimeter thereof. The taper portion 14 b makes a small angle of 3 to 20degrees, for example, 10 degrees with the flat portion 14 a. A diameterof an end 14 c at an inner perimeter side of the taper portion 14 bapproximately matches that of an end 24 a at an inner perimeter side ofthe sandwiching face 24, and from the end 14 c across the innerperimeter face 13 a of the barrel 10, a chamfer 15 is formed that makesan angle of 60 degrees with the flat portion 14 a.

In addition, it is preferable to set a longitudinal direction distanceof the barrel 10 that retreats from the flat portion 14 a to the end 14c so as to be a same degree as a thickness of the porous membrane F andso that the end 14 c abuts with a surface of the membrane F afterwelding the barrel 10 and the cap 20.

Although such an outer diameter of the opening edge 14 of the barrel 10is decided according to a process liquid amount and a filtration time,in a case of fixing the barrel 10 and the cap 20 by ultrasonic welding,it is preferable to press the flat portion 14 a to the porous membrane Fand vibrate the portion 14 a, and to thereby set a width of the portion14 a to a size suitable for the membrane F melting. For example, in acase that the outer diameter of the opening edge 14 is 7 mm, the widthof the flat portion 14 a is preferably 0.02 to 1 mm. This is because afiltration effective area decreases if the width of the flat portion 14a is made too wide. Furthermore, considering a manufacturing adequacysuch as an energy added to the barrel 10 in welding, the width of theflat portion 14 a is preferably 0.02 to 0.5 mm, and more preferably 0.02to 0.2 mm.

Next will be described an assembling method of the porous membrane F,the barrel 10, and the cap 20 thus described, referring to FIG. 4 andFIG. 5 showing an assembling process of the porous membrane cartridge 1.

As shown in FIG. 4, dispose the porous membrane F so as to be put on thebottom portion 26 of the cap 20. At this time, because the sandwichingface 24 and the ribs 25 are designed higher than the bottom portion 26by one step, the porous membrane F is, to be more precise, put on thesandwiching face 24 and the ribs 25. Then because the diameter of theporous membrane F is approximately same as the inner diameter of the cap20, as shown in FIG. 5 (a), a peripheral edge Fa of the porous membraneF results in being positioned on the sandwiching face 24.

Then fitting the top end 13 of the barrel 10 inside the fit-in portion22 of the cap 20, make the opening edge 14 of the barrel 10 abut withthe peripheral edge Fa of the porous membrane F. In such a temporalassembly, perform welding by an ultrasonic welder not shown. Forexample, set the cap 20 on a platform for pressurizing of the ultrasonicwelder, apply an ultrasound while pressurizing the barrel 10 toward thecap 20 by horn.

Whereat, by pressing the barrel 10 to the cap 20, an air gap of theporous membrane F is crushed, and then as shown in FIG. 5 (b), theperipheral edge Fa of the outmost perimeter of the porous membrane F iscrushed. At this time, because the flat portion 14 a provided at theoutmost perimeter of the opening edge 14 sandwiches the porous membraneF between itself and the sandwiching face 24, a position of the membraneF is decided, and an unnecessary positional displacement of the membraneF is prevented. Then part of the porous membrane F is further crushed asshown in FIG. 5 (c) while melting, and the opening edge 14 abuts withthe sandwiching face 24. Subsequently, a peripheral edge including theflat portion 14 a of the opening edge 14 and that of the sandwichingface 24 melt and are welded. As a result, as shown in FIG. 5 (d), theopening edge 14 of the barrel 10 and the sandwiching face 24 of the cap20 sandwich the porous membrane F, and the membrane F is held in a stateof its peripheral edge Fa being crushed. Also the porous membrane Fexisting between the taper portion 14 b of the opening edge 14 and thesandwiching face 24 is also compressed by the taper portion 14 b andpart of an air gap is crushed. Then the end 14 c is in contact with thesurface of the porous membrane F. At this time, because the end 14 c isformed as a blunt angle by the chamfer 15, it is difficult to damage theporous membrane F.

The porous membrane cartridge 1 thus made is used as follows:

Firstly, as sample solutions containing nucleic acids, prepare bodyfluids such as a whole blood, plasma, serum, urine, human waste, semen,and saliva taken as analytes; or solutions adjusted from bioticmaterials such as a soluble matter and homogenate of a vegetable (or itspart), an animal (or its part), and the like. Treat these solutions witha water solution containing a reagent, which solves a cell membrane andsolublizes the nucleic acids. Thus the cell membrane and nucleicmembrane are solved, and the nucleic acids are dispersed in the watersolution. For example, when a sample is a whole blood, red blood cellsand various proteins are removed and white blood cells and nucleicmembranes are solved by incubation of 10 minutes at 60 degrees Celsiusin a state of addition of Guanidine Hydrochloride, Triton-X100, andProtease K (manufactured by SIGMA Corp.).

Adding a water soluble organic solvent, for example, ethanol to a watersolution where nucleic acids are thus dispersed, a sample solution iscompleted. Pass the sample solution while applying a pressure from theopening 11 b at the rear end side of the barrel 10 toward the opening 21a of the top of the nozzle 23. Thus the nucleic acids in the samplesolution are adsorbed to the porous membrane F.

In a pressurizing system of passing a sample solution by applying thepressure with being compared to a centrifugal separation system thatpasses the solution by centrifugal force, although the solution attemptsto flow toward the peripheral edge Fa of the porous membrane F, becausein the portion Fa of the porous membrane F the end portion 14 c of thebarrel 10 is in contact with the surface of the membrane F, the solutioncannot enter a space between the membrane F and the opening edge 14 ofthe barrel 10. In addition, because in the peripheral edge Fa of theporous membrane F an air gap is crushed by the taper portion 14 b andthe sandwiching face 24 and furthermore the outer perimeter portionthereof is completely closed by welding of the barrel 10 and the cap 20,it does not occur that a sample solution goes around a side portion(edge of the outer perimeter) of the membrane F. Accordingly, nucleicacids in a sample solution result in being adsorbed only to an insideportion surrounded by the end 14 c of the barrel 10 out of the porousmembrane F.

Next, pass a nucleic acid washing buffer while applying a pressure fromthe opening 11 b at the rear end side of the porous membrane cartridge 1toward the opening 21 a of the nozzle 23. Although the nucleic acidwashing buffer has a composition of desorbing not nucleic acids adsorbedto the porous membrane F but impurities, it is composed of a watersolution containing a main agent and a buffer agent, and a surfactant asneeded. As the main agent, a solution containing ethanol, Tris, andTriton-X100 is preferable. By this operation, impurities other thannucleic acids are removed from the porous membrane F.

At this time, out of the porous membrane F, because a nucleic acidwashing buffer sufficiently passes a portion where the sample solutionpassed, that is, a portion surrounded by the end 14 c, impurities areremoved without remaining at the peripheral edge Fa of the membrane F.

Next, passing any one of such refined distilled water and a TE buffer(containing Tris and EDTA (ethylenediamine tetraacetic acid)) whileapplying a pressure from the opening 11 b toward the opening 21 a (seeFIG. 2), desorb nucleic acids from the porous membrane F, desorb theacids and make them flow out, and recover a solution containing theflowed-out nucleic acids. At this time because same as in adsorbingnucleic acids to the porous membrane F, such refined distilled watersufficiently passes through a portion where the acids surrounded by theend 14 c out of the porous membrane F, the acids are sufficientlydesorbed without remaining at the peripheral edge Fa of the membrane F.

Thus in the porous membrane cartridge 1 of the embodiment, because whenpassing such a sample solution where nucleic acids is dispersed, anucleic acid washing buffer, and refined distilled water, they do not goaround a side portion of the porous membrane F, it does not occur that:the acids are discharged without being adsorbed to the membrane F, andimpurities mix in a solution where the acids are recovered. In addition,because the end 14 c is in contact with the porous membrane F and itdoes not also occur that the various liquids described above enter aspace between the membrane F and the opening edge 14 of the barrel 10,impurities do not mix in a nucleic acid solution after the recovery, anda nucleic acid recovery efficiency is also higher.

In addition, in the porous membrane cartridge 1 of the embodiment,because part of the opening edge 14 is formed so as to be the taperportion 14 b where an inner perimeter side is more retreated than anouter perimeter side and a sandwiching force by the opening edge 14 andthe sandwiching face 24 gradually becomes smaller from an outerperimeter to an inner perimeter, it is enabled to avoid a concentrationof a stress applied to the porous membrane F. In addition, because thatthe opening edge 14 is designed to be a blunt angle also alleviates theconcentration of the stress applied to the porous membrane F, it isenabled to prevent the membrane F from breaking.

In addition, in a case of using the porous membrane cartridge 1 infiltration, because a liquid does not go around the side portion of theporous membrane F, mixing of impurities in a liquid after the filtrationbecomes less.

The first embodiment thus described is one example of the presentinvention, and because it suffices that the invention may fix the barrel10 and the cap 20 in a state of crushing and sandwiching the porousmembrane F, various variation examples as below can be considered.Meanwhile, in embodiments below with respect to a same portion as in thefirst embodiment, a detailed description thereof will be omitted,appending a same symbol.

Second Embodiment

FIG. 6 is drawings showing a porous membrane cartridge 1A related to asecond embodiment of the present invention, and is section viewscorresponding to the enlarged view of the part A in FIG. 2. As shown inFIG. 6 (a), in the porous membrane cartridge 1A of the second embodimenta bead 16 a of which a section is chevron is provided across a wholeperimeter in the vicinity of an outer perimeter of an opening edge 16 ofthe barrel 10. Then an inner perimeter side of the bead 16 a is designedto be a flat portion 16 b for orthogonalizing an axial line of thebarrel 10.

In a case of assembling such the porous membrane cartridge 1A, disposingthe porous membrane F at the bottom portion 26 of the cap 20 and fittingthe top end 13 of the barrel 10 in the fit-in portion 22 of the cap 20,sandwich the membrane F between the opening edge 16 and the sandwichingface 24.

Then if applying an ultrasound to the barrel 10 by horn while pressingthe opening edge 16 to the sandwiching face 24 in order to weld the cap20 and the barrel 10 by ultrasonic welder, the bead 16 a melts andpenetrates the porous membrane F, and as shown in FIG. 6 (b), thesandwiching face 24 and the bead 16 a are welded. If further making thewelding proceed, the flat portion 16 b crushes and sandwiches the porousmembrane F between itself and the sandwiching face 24 as shown in FIG. 6(c).

Also in the porous membrane cartridge 1A thus made, because the openingedge 16 and the sandwiching face 24 are welded while the peripheral edgeFa of the porous membrane F melts, a liquid does not go around a sideportion of the porous membrane F. In addition, because the porousmembrane F is sandwiched between the flat portion 16 b and thesandwiching face 24 while crushed between them, a liquid does not enterthe portion Fa of the membrane F.

Accordingly, also in the porous membrane cartridge 1A of the embodiment,a recovery efficiency of nucleic acids is better and mixing ofimpurities in a solution after a recovery is less.

In addition, in a case of using the porous membrane cartridge 1A infiltration, mixing of impurities in a liquid after the filtrationbecomes less.

Meanwhile, in a case of providing such a bead are available not only amode of providing the bead at the opening edge 16 of the barrel 10 butalso a porous membrane cartridge 1C of a mode where a bead 24 b of whicha section is chevron across a whole perimeter in the vicinity of theouter perimeter of the sandwiching face 24 without providing the bead atthe opening edge 16 as shown in FIG. 7.

Third Embodiment

FIG. 8 is drawings showing a porous membrane cartridge 1D related to athird embodiment of the present invention and corresponding to theenlarged view of the part A in FIG. 2. The porous membrane cartridge 1Dis a mode of welding the barrel 10 and the cap 20 at a portion of anouter perimeter more than the sandwiching face 24.

In other words, as shown in FIG. 8 (a), in the cap 20 is formed a stepportion 27 for welding defined by: a wall face portion 27 aperpendicularly rising up with respect to the sandwiching face 24 atoutside of the sandwiching face 24; and a slant portion 27 b slantedlyrising up toward the inner perimeter of the fit-in portion 22 from anupper end (namely, the rear end) in FIG. 8 (a) of the wall face portion27 a.

On the other hand, at an opening edge 17 of the barrel 10 are formed aflat portion 17 a parallel with the sandwiching face 24 formed at aninner perimeter side; a wall face portion 17 b composed of a peripheralface for fitting in the wall face portion 27 a formed with continuingfrom an outer perimeter end of the flat portion 17 a; a slant portion 17c formed with continuing from the top end in FIG. 8 (a) of the wall faceportion 27 a and parallel with the slant portion 27 b; and a flatportion 17 d formed with continuing into the slant portion 17 c andextending toward the outer perimeter of the barrel 10.

If such the porous membrane cartridge 1D sandwiches the porous membraneF between the sandwiching face 24 and the flat portion 17 a, and thebarrel 10 and the cap 20 is applied to an ultrasonic welder, the flatportion 17 d abuts with the slant portion 27 b and the abutment portionis welded. Then the peripheral edge Fa of the porous membrane F issandwiched between the flat portion 17 a and the sandwiching face 24 ina state of being crushed.

Thus only sandwiching and holding the porous membrane F and welding thebarrel 10 and the cap 20 at an outer portion more than the membrane F,it does not occur to damage the membrane F also in a case that it isespecially delicate.

Furthermore, as a mode of fixing the barrel 10 and the cap 20 at outsideof the porous membrane F are cited modes shown in FIG. 9.

For example, as shown in FIG. 9 (a), it is also enabled to make the mainbody 12 of the barrel 10 and a face of a step difference of an outerperimeter face of the top end 13 a joint portion 18 for welding, on theother hand to form a protrusion abutting with the portion 18 across awhole perimeter at an opening edge 28 at a rear end side of the cap 20,and to thus make a porous membrane cartridge 1E where the joint portion18 and the opening edge 28 are welded.

In addition, as shown in FIG. 9 (b), form a bead 19 composed of a gentlecircular section along a peripheral direction across a whole perimeterat an outer perimeter of the top end 13 of the barrel 10, and on theother hand, in advance form a corresponding depression groove 29 at aportion corresponding to the bead 19 on an inner perimeter face of thefit-in portion 22 of the cap 20. Then by an engagement between the bead19 and the depression groove 29, it is enabled to sandwich the porousmembrane F between the opening edge 14 and the sandwiching face 24 in astate of crushing the outer perimeter edge of the membrane F.

Because such a porous membrane cartridge 1F is enabled to be assembledby hand, it is convenient in small production.

Thus, although the embodiments of the present invention are described,the invention is not limited thereto, and it can be carried out withbeing appropriately varied.

For example, the barrel 10 and the cap 20 can also be made to adhere byany one of an adhesive and a UV curing resin, and the outer perimeterface of the top end 13 of the barrel 10 and the inner perimeter face ofthe fit-in portion 22 of the cap 20 can also be welded by laser.Meanwhile, in a case of laser welding, it is preferable to make thebarrel 10 a material that can generate heat by absorbing laser or toblend a plasticizer in the barrel 10.

EXAMPLE

Next will be described one example of the present invention.

In the example, manufacturing a porous membrane cartridge of a shape inthe first embodiment and changing a welding condition at that time, atest for determining whether welding was good or bad was performed.

As a material of the barrel 10 and the cap 20 was used polystyrene(manufactured by A&M Styrene Co., Ltd.). The outer diameter of theopening edge 14 of the barrel 10 was made 7 mm, the width of the flatportion 14 a at outer perimeter side of opening edge 14 was made 0.05mm, and as shown in FIG. 5 (a), the angle of the taper portion 14 b wasformed to be 10 degrees for the flat portion 14 a.

As the porous membrane F was used triacetylcellulose (Microfilter FM500manufactured by Fuji Photo Film Co., Ltd.).

Using an ultrasonic welder (40 KHz, 800 KW) manufactured by BransonCorp. as an ultrasonic welder, disposing the porous membrane F at thebottom portion 26 of the cap 20 same as in the first embodiment, andfitting the top end 13 of the barrel 10 in the cap 20, the barrel 10 wasvibrated while pressed toward the cap 20 by a horn of the ultrasonicwelder. Changing a pressing force and a vibration time at this time, awelding result under each condition was determined.

Table 1 shows the result. TABLE 1 Pressing Force (N) 50 75 100 150 200Vibration 0.03 X X X X X Time (sec) 0.05 X X ◯ ◯ ◯ 0.1 X X ◯ ◯ ◯ 0.15 X◯ ◯ ◯ ◯ 0.2 Δ ◯ ◯ ◯ ◯ 0.25 Δ ◯ ◯ ◯ ◯ 0.3 Δ ◯ ◯ ◯ □ 0.35 Δ ◯ ◯ ◯ □ 0.4 Δ◯ ◯ □ □ 0.45 Δ ◯ ◯ □ □ 0.5 Δ □ □ □ □ 0.6 Δ □ □ □ □X Unable to be WeldedΔ Liquid Leakage□ Perforation of Porous Membrane and Deformation of Molded Product◯ Good

As shown in Table 1 were changed the pressing force between 50 N and 200N and the vibration time between 0.03 sec and 0.6 sec. In Table 1, thesymbol x indicates that the barrel 10 and the cap 20 could not bewelded; the symbol Δ indicates that although the barrel 10 and the cap20 could be welded, the welding was insufficient and there was a liquidleakage from the welded portion; the symbol □ indicates that there was adefect that the porous membrane F was perforated or a formed product wasdeformed; and the symbol O indicates that the welding could be performedwell without the defect.

As seen from Table 1, in a case of the pressing force of 50 N, thewelding could not be performed or there was a liquid leakage, and anycase of the vibration time was bad.

In a case of the pressing force of 75 N, the welding could not beperformed in a case of the vibration time not more than 0.1 sec andcould be performed well in a case of the vibration time between 0.15 secand 0.45 sec; in a case of the vibration time not less than 0.5 sec, awelding time was too long and there was the defect in a formed product.

In a case of the pressing force of 100 N, the welding could not beperformed in a case of the vibration time of 0.03 sec and could beperformed well in a case of the vibration time between 0.05 sec and 0.45sec; in a case of the vibration time not less than 0.5 sec, a weldingtime was too long and there was the defect in a formed product.

In a case of the pressing force of 150 N, the welding could not beperformed in a case of the vibration time of 0.03 sec and could beperformed well in a case of the vibration time between 0.05 sec and 0.35sec; in a case of the vibration time not less than 0.4 sec, a weldingtime was too long and there was the defect in a formed product.

In a case of the pressing force of 200 N, the welding could not beperformed in a case of the vibration time of 0.03 sec and could beperformed well in a case of the vibration time between 0.05 sec and 0.25sec; in a case of the vibration time not less than 0.3 sec, a weldingtime was too long and there was the defect in a formed product.

Thus in a case of the pressing force between 75 N and 200 N, goodwelding was enabled if between a predetermined vibration time, and as aresult, it was enabled to manufacture a preferable porous membranecartridge where a liquid leakage does not occur.

1. A porous membrane cartridge comprising: a cylindrical barrel havingopenings at a top end and a rear end, respectively; a cap formed into acylindrical shape having a fit-in portion fitted outside said top end,abutting with an opening edge of said top end, and having a sandwichingface for sandwiching a porous membrane between itself and said barrel;and said porous membrane sandwiched between the opening edge of saidbarrel and said cap, wherein said cap is fixed to said barrel so as notto be pulled out of the barrel in a state of crushing a peripheral edgeof said porous membrane and sandwiching the porous membrane betweenitself and said cap.
 2. The porous membrane cartridge according to claim1, wherein the opening edge of said barrel and the sandwiching face ofsaid cap are welded by ultrasound.
 3. The porous membrane cartridgeaccording to claim 2, wherein in addition that the opening edge of saidbarrel is formed to a taper where an inner perimeter side is moreretreated than an outer perimeter side, said opening edge is welded tothe sandwiching face of said cap.
 4. The porous membrane cartridgeaccording to claim 3, wherein said taper is formed with continuing intoa flat portion formed at an outmost perimeter of said opening edge. 5.The porous membrane cartridge according to claim 2, wherein in additionthat a bead portion as an energy director is circularly formed on anyone of said opening edge and said sandwiching face, and said porousmembrane is sandwiched and crushed with the bead portion, said cap andsaid barrel are welded by ultrasound
 6. The porous membrane cartridgeaccording to claim 1, wherein said barrel comprises a joint portion,which is configured to abutting with an opening edge of the fit-inportion of said cap, on an outer perimeter of the barrel, and said capand said barrel are made to adhere or are welded by the opening edge ofsaid fit-in portion and said joint portion.
 7. The porous membranecartridge according to claim 1, wherein said cap is fixed to said barrelby an engagement between any one of a depression and a protrusion formedon an outer perimeter face of said barrel and any one of a depressionand a protrusion formed on an inner perimeter face of said cap.
 8. Theporous membrane cartridge according to claim 1, wherein said cap andsaid barrel are made to adhere by adhesive.
 9. The porous membranecartridge according to claim 1, wherein after said cap and said porousmembrane are inserted in a cavity of an injection molding mold, a shapeof a portion of said barrel is molded by injecting a molding material insaid cavity.